Gaining

Just start eating larger portions.
The is no one magical thing to make you gain.
It takes time and effort on your part to gain and how fast you gain is up to your body and your metabolism.

Think about getting some gainer shakes if you have a hard time eating enough food drinking calories like having milk, pop ect is a great way to start increasing your caloric intake and in turn increasing your appetite! Make sure to have a high calorie drink with every meal! Enjoy the food you eat! Don’t just eat it cus it’s fattening! Try melting ice cream and drinking it! Have snacks and don’t eat until you’re uncomfortable if you’re not feeling it! Sometimes eating less in one sitting means there is room for snacks later which you usually end up eating more in the long run!

Heavy cream. Small portions, spread out across the day. It works like magic.